WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7150
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Article Citation - WoS: 9Citation - Scopus: 11A Qualitative Survey on Frequent Subgraph Mining(De Gruyter, 2018) Güvenoğlu, Büşra; Ergenç Bostanoğlu, BelginData mining is a popular research area that has been studied by many researchers and focuses on finding unforeseen and important information in large databases. One of the popular data structures used to represent large heterogeneous data in the field of data mining is graphs. So, graph mining is one of the most popular subdivisions of data mining. Subgraphs that are more frequently encountered than the user-defined threshold in a database are called frequent subgraphs. Frequent subgraphs in a database can give important information about this database. Using this information, data can be classified, clustered and indexed. The purpose of this survey is to examine frequent subgraph mining algorithms (i) in terms of frequent subgraph discovery process phases such as candidate generation and frequency calculation, (ii) categorize the algorithms according to their general attributes such as input type, dynamicity of graphs, result type, algorithmic approach they are based on, algorithmic design and graph representation as well as (iii) to discuss the performance of algorithms in comparison to each other and the challenges faced by the algorithms recently.Article Citation - WoS: 1Experimental Verification of Lead-Lag Compensators on a Twin Rotor System(De Gruyter, 2018) Deniz, Meryem; Tatlıcıoğlu, Enver; Bayrak, AlperTwin rotor system is a laboratory setup resembling a simplified helicopter model that moves along both horizontal and vertical axes. The literature on control of twin rotor systems reflects a good amount of research on designing PM controllers and their extensions considering several aspects, as well as onsome nonlinear controllers. However, there is almost no previous work on design of lag-lead type compensators for twin rotor systems. In this study, by considering this open research problem, lag and lead type compensators are designed and then experimentally verified on the twin rotor system. Specifically, first, lag and lag-lag compensators are designed to obtain a reduced steady state error as compared with proportional controllers. Secondly, lead compensation is discussed to obtain a reduced overshoot. Finally, lag-lead compensators are designed to make use of their favorable properties. All compensators are applied to the twin rotor system in our laboratory. From experimental studies, it was observed that steady state error was reduced when a lag compensator was used in conjunction with a lead compensator.Article A Quantitative Balian-Low Theorem for Higher Dimensions(De Gruyter, 2020) Temur, FarukWe extend the quantitative Balian-Low theorem of Nitzan and Olsen to higher dimensions. We use Zak transform methods and dimension reduction. The characterization of the Gabor-Riesz bases by the Zak transform allows us to reduce the problem to the quasiperiodicity and the boundedness from below of the Zak transforms of the Gabor-Riesz basis generators, two properties for which dimension reduction is possible. © 2018 Walter de Gruyter GmbH, Berlin/Boston 2018.Article Citation - WoS: 5Citation - Scopus: 6Oxo-Bridged (haloarylimido)[tris(3,5-Dimethylpyrazolyl)borato] Molybdenum(v) Complexes: Crystal Structures of Geometric Isomers of [motp*(o)cl](µ-O)[motp*(cl)(?nc6h 4br)](De Gruyter, 2005) Sözüer, Hikmet Işıl; Dülger İrdem, Seçkiner; Jeffery, John J.; Hamidov, Hayrullah; Şentürk, Ozan SanlıThe reaction between [MoTp*(O)Cl2], [Tp* = hydrotris(3,5-dimetylpyrazol-1-yl)borate] and 4-bromoaniline in refluxing toluene gave geometric isomers of [MoTp*(O)Cl](μ-O)[MoTp*(Cl) (≡NC6H4Br)] (1a, cis; 1b, trans), but a similar reaction between [MoTp*(O)Cl2] and 4-chloroaniline yielded only one product, [MoTp*(O)Cl](μ-O)[MoTp*(Cl)(≡NC 6H4Cl)] (2) as a red crystalline solid. The new compounds were characterized by microanalytical data, mass, IR and 1H NMR spectroscopy. The X-ray structure analysis of 1a and 1b revealed that the complexes are geometric isomers, the two chloro ligands being cis in 1a and trans in 1b. Both compounds have Mo-O-Mo linkages and nearly linear arylimido moieties.